Building unit



- June 23, 1959 0.1.. RICHTER 2,891,491-

BUILDING UNIT Filed May-'5, 1955 2 Sheets-Sheet 2 DONALD L. fi/cflrnz a g 2,891,491 Ice Patented June 23, 1959 BUILDING UNIT Don L. Richter, Walnut Creek, Calif.

Application May 5, 1955, Serial No. 506,194

9 Claims. (Cl. 108-1) This invention relates to a structural building unit for buildings or storage shelters or portions thereof such as roofs, floors and walls or combinations thereof. The invention provides a unit of this kind which is stronger when made of a given amount of an appropriate material and at the same time easier to form than most similar building units previously known to the art.

Many building units aim at great strength with light weight or economy of material but necessarily take geometrical forms that are expensive to make and cannot be practically made with materials, techniques and skills now commercially available. Thin membranes of compound curvature are often resorted to and are satisfactory theoretically butare prohibitively expensive to make in varying sizes and in large quantities by present facilities. In some instances they are structurally unstable.

An object of the present invention is to provide a building unit that is light and strong yet can be easily fabricated by available means.

Another object of the invention is to provide a building unit having a membrane with many of the good properties of a membrane of compound curvature yet which can be readily formed.

Another object of the invention is to provide a building unit gaining strength from an unusual shaping of the constituent material yet one in which the shape is easily and cheaply formed in various sizes and in large quantities.

Other objects together with the foregoing are attained in the embodiments of the invention described in the accompanying description and illustrated in the accom panying drawings in which:

Figure 1 is a perspective view of a building unit according to the invention;

Figure 2 is a top plan view of the building unit;

Figure 3 is a front view of the building unit;

Figure 4 is a bottom plan view of the building unit;

Figure 5 is a side view of the building unit;

Figure 6 is a perspective view of a building formed of the building units of the invention;

Figure 7 is a geometrical diagram in perspective illustrating parts of the building unit of the invention.

In the form of the invention shown herein, a building unit, generally designated 10 comprises a membrane 11 of metal or plastic. This is usually one continuous sheet but may be made up of many strips or several small panels. The membrane is supported by and is secured to a frame. This conveniently is quadrilateral and is composed of straight or approximately straight frame members. The side frame members 12 and 14 are substantially parallel when seen in plan although they are not necessarily of equal length. The end frame members 13 and 15 are also substantially parallel when seen in plan but also are not necessarily of equal length. The side frame members and the end frame members are secured together at their ends and to define a skew figure. This may be described or visualized in several ways. If an originally planar quadrilateral frame is first supported at diagonal corners and the two remaining corners are then depressed below the original plane, a somewhat similar skew frame results. If the sides and ends of the planar frame are lengthened as they are depressed, the frame will retain its original appearance when projected onto the original plane. A similar result is obtained if two diagonal corners are depressed below the original plane and the other two diagonal corners are lifted equally above the original plane. In the original flat frame, the diagonals lie in the plane and intersect. When the diagonal corners are moved out of (above and below) the original plane, the diagonals also move apart and respectively lie above and below the original plane. In this space relationship the four sides of the skewed frame and the two diagonals define the boundary edges of a tetrahedron. This is shown in Figures 2 and 7. For example, the end frame members 13 and 15 meet the side frame member 12 in corners 16 and 17 while they meet the side frame member 14 in corners 18 and 19. Diagonals can be imagined from 16 to 18 and from 17 to 19. These diagonals are not necessarily of equal length. In Figure 7 the skewed frame members are in heavy broken lines and the diagonals in light broken lines. For example, the raised corners 16 and 18 are connected by a diagonal 24 while the lowered corners 15 and 17 are connected by a diagonal 25. The members 14, 15 and 24 define a triangular plane surface 20, the members 13, 14 and 25 define a triangular plane surface 21; the members 12, 13 and 24 define a triangular plane surface 23 While the members 12, 15 and 25 define a plane triangular surface 22. All of the surfaces 20, 21, 22 and 23 enclose a tetrahedron. Hence, the end and side members of the frame (exclusive of the diagonals) can be considered as four sides of a tetrahedron. These four tetrahedron sides may or may not be a parallelogram when seen in plan but always constitute a quadrilateral and may be skewed (or have diagonally opposite corners displaced from a plane) any desired amount.

On a skewed frame made up of the side frame members 12 and 14 and of the end frame members 13 and 15, I preferably provide the membrane 11 also in skewed form. To press, stretch, machine or cast a compound curved, smooth membrane of this sort is expensive and difiicult. Pursuant to my invention, I provide the membrane 11 by starting with a corrugated sheet; for example, of ordinary corrugated steel or aluminum. This can be the customary rectangular (or approximately so) sheet having substantial corrugations therein all running parallel to the side edges of the sheet from end to end, the corrugations in cross-section presenting a wavy, semi-cylindrical or sinusoidal or other convenient form and being of uniform profile or form along the entire length of the sheet. Then the sheet is skewed by depressing (for example) the diagonally opposite corners and the sheet is transversely expanded more and more as its ends are approached. This results in gradually greater flattening of the corrugations toward the ends. In an extreme case, the corrugations can virtually disappear at the end edges of the sheet although across the middle of the sheet they have substantially the original depth and pitch. Figures 2 and 4 show in fiat projection the fan shape rearrangement of the corrugations by this operation. This shape change is easily done because of the inherent flexibility across the corrugations, i.e. the membrane is a developable member. Alternatively, the corrugations may be flattened less toward the ends of the sheet and gathered or pressed closer together with greater height across the center of the sheet.

In any case, the sheet is readily deformed into a skew contour to lit the frame within commercial tolerances so that the two can be fastened together in directly abutting relationship by means of welding, or the like. Preferably all four sides of the corrugated membrane are fastened to all of the frame members either continuously or at very close intervals. Slight discrepancies in shape are permitted as the membrane 11 overlies more or less of the width of the frame members to which it is fastened. The skewing of the membrane makes the resulting panel upwardly concave between the corners 16 and 1 8 and downwardly concave between the corners 17 and 19. Also, it is upwardly convex along the diagonal and is downwardly convex along the diagonal 24.

There results a building construction unit easily formed of virtually standard material readily given the desired skew contour for great strength with lightness and economy yet one which avoids the almost impossible task, commercially, of making a compound curved surface. However, when seen from suflicient distance so that the corrugations are not especially noticeable, the present building construction unit appears to present virtually a compound curved surface, as observable in the present drawings.

The building unit can be readily assembled with other comparable units, as shown in Figure 6. A shelter roof is made up of a number of units 32. preferably (although not necessarily) arranged symmetrically about an apex 31 with the adjacent frame members 33 substantially in a plane. The diagonals of the various units for this arrangement are unequal in length but not beyond the bounds of practicality. The unequal diagonals and the amount of skew place the successive edges 34 and 35 in a straight line through a point 36, making the building a hexagon in plan.

I claim:

1. A structural building unit comprising a quadrangular frame including a pair of longitudinal side members and a-pair of transverse end members joined with the diagonal corners in different planes, and a membrane secured at its edges to all of said members, said membrane including a sheet having corrugations throughout running substantially longitudinally of said sheet and of a greater amplitude in the transverse central part of said sheet than in the transverse end parts of said sheet.

2. A structural building unit comprising a quadrangular frame including a pair of longitudinal side members arranged in approximate parallelism when seen in plan and arranged in non-parallelism when seen in side elevation, and a pair of transverse end members arranged to connect the adjacent ends of said side members, and a membrane secured at its edges to all of said members, said membrane for its entire length having longitudinally extending corrugations of a lesser pitch measured transversely near the center of said membrane than when measured transversely near the ends of said membrane.

3. A structural building unit comprising a quadrangular frame including a pair of substantially straight longitudinal side members and a pair of substantially straight transverse end members connected to said side members to provide four corners, one of said side members and one of said end members lying substantially in one of two dihedral planes intersecting on a line passing through diagonal ones of said corners and the other of said side members and the other of said end members lying substantially in the other of said dihedral planes, and a membrane abutting and connected peripherally to said members, said membrane having approximately parallel corrugations extending longitudinally thereof and of a greater pitch when measured transversely at the ends of said membrane than when measured transversely adjacent the center of said membrane.

4. A structural building unit comprising a membrane of a sheet of uniformly thick material and having a contour when viewed in plan that is quadrilateral with substantially parallel side edges and substantially parallel end edges and having throughout corrugations of a pitch increasing from the center toward said end edges and extending parallel with said side edges and disposed with one pair of diagonal corners of said sheet in a predetermined plane and with the other pair of diagonal corners of said sheet in another plane parallel to said predetermined plane.

5. A structural building unit as in claim 4 in which the edges of said membrane are secured to a quadrilateral frame substantially registering therewith in plan.

6. A structural building unit as in claim 4 in which the edges of said membrane are secured to a quadrilateral frame of substantially straight members of approximately the same contour as said edges.

7. A method of making a structural building unit including providing a planar quadrilateral sheet of deformable material having substantially parallel side edges and substantially parallel end edges, then corrugating' said sheet throughout with uniform corrugations extending substantially parallel with said side edges, then deforming said corrugations by displacing diagonal corners of said sheet in the same direction out of the original plane into new positions in registry in plan with the original positions of said corners.

8. A method of making a structural building unit as in claim 7 including the further step of securing the edges of said sheet to a quadrilateral frame of substantially straight members of approximately the same contour as said edges.

9. A building at least partially enclosing a volume and comprised of a plurality of structural building units having peripheral quadrilateral frames joined together, said structural building units each including a corrugated sheet secured at its edges to said frame and with said frame having a contour defined by displacement of two diagonal corners in one direction and having corrugations approximately parallel with each other and of a greater pitch acrossthe ends of said sheet than across the central portion thereof.

References Cited in the file of this patent UNITED STATES PATENTS 992,421 Hardie May 16, 1911 1,714,204 Auger May 21,1929 2,093,836 Guyon i Sept. 21, 1937 FOREIGN PATENTS 450,290 Italy July 12, 1949 678,325 Great Britain Sept. 3, 1952 OTHER REFERENCES EngineeringNews Record, I an. 1, 1953, page 25; 

